// 定义懒加载插件
import {useIntersectionObserver} from '@vueuse/core'

export const lazyPlugin = {
    install(app) {
        // 懒加载指令逻辑
        app.directive('img-lazy', {
            mounted(el, binding){
                //el: 指令绑定的那个元素  img
                // binding: binding.value 指令等于号后面绑定的表达式的值 图片url
                console.log(el, binding.value);
                const {stop} = useIntersectionObserver(el, ([{isIntersecting}]) => {
                    console.log(isIntersecting);
                    if(isIntersecting){
                        // 进入视口区域
                        el.src = binding.value
                        stop()
                    }
                })
            }
        })
    }
}